Airbags are used in vehicles to cover the interior side surface in a vehicle in case of an accident to prevent severe injuries of the occupant. The airbag is mounted above the side windows at a rim of the vehicle structure under the rooflining. As the installation space for the airbag is very limited especially in small cars, the airbag is rolled or folded to a long thin cylinder-shaped package.
For pedestrian protection, airbags are further located at the lower edge of the windshield, which in the event of an accident deploy on the windshield and in the inflated state cover the windshield as well as the pillars of the motor vehicle towards the outside.
One possible embodiment of an airbag, in this case a curtain airbag, and a device for folding or rolling an airbag is known from the WO 2009/083056 A1. The airbag is rolled from a flat structure to a thin cylinder in a device comprising several deflection pulleys and a traction mechanism. The traction mechanism consists of several belts arranged in distances on a basis, wherein the arrangement and the number of the belts depend on the individual shape and dimension of the airbag. The tightness of the airbag in the cylinder shape depends on the traction mechanism and especially on the design and arrangement of the deflection pulleys.